JPH05240658A - Electronic odometer - Google Patents

Abstract

PURPOSE:To facilitate read-out of data within a nonvolatile memory in an instrument which writes an integrated driving distance data into the nonvolatile memory and holds the data. CONSTITUTION:An electronic odometer is provided with a driving distance sensor 1, a nonvolatile memory (memory part 3) where an integrated driving distance data is written, an operation processing part 2 which reads out the data within the memory part 3, calculates the newest driving distance of the vehicle, and rewrites the data into the memory, and a display 4 which displays the newest integrated during distance. Then, the memory part 3 consists of memory parts 31, 32, 33, 34, 35, and 36 which are divided for each digit of a displayed numeric so that a data numeric of each memory part 31, etc., becomes the display numeric immediately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic odometer which is mounted on a vehicle and displays the total traveling distance of the vehicle.

[0002]

2. Description of the Related Art An electronic odometer uses a vehicle speed sensor that generates a pulse at every constant traveling distance of a vehicle as a distance sensor at the same time, and counts and integrates the number of input pal from this sensor to calculate the traveling distance of the vehicle. However, the accumulated traveling distance at that time is sequentially added to the previous accumulated traveling distance, and the traveling distance is displayed by an appropriate display device.

By the way, the mileage data is written in an appropriate non-volatile memory for each predetermined mileage so as not to be lost, and the data stored in the non-volatile memory when the vehicle starts to run (when the ignition switch is turned on). It reads and displays the total traveled distance based on this.

An EEPROM is often used as a non-volatile memory, and erasing and writing of mileage data is repeated to always store the latest data. However, since there is a limit to rewriting the EEPROM, it has been more than before. Various rewriting methods to the EEPROM have been proposed.

For example, Japanese Patent Publication No. 1-29407 discloses that
An n × n lower digit memory and an upper digit memory with a small capacity are provided, and “0” to “1” is written in 1-bit units of the lower digit memory for each predetermined traveling distance. There is disclosed a method in which when the writing of 1 is completed, one unit is written in the upper digit memory, the lower digit memory is completely erased, and writing to the lower digit memory is started again. In addition, the above-mentioned 1-46005 gazettes and 1-46006.
In the publication, a plurality of memory groups are adopted as the lower digit memory and the upper digit memory, and writing to the upper digit memory is performed every predetermined writing of the lower digit memory, and each first and second memory A single group is used for each group, and when one memory group overflows, the next memory group is used for the next writing, and the number of times of rewriting the memory is set to the limit or less.

[0006]

By the way, the above-mentioned writing means for each non-volatile memory is a division of the upper and lower digits based on the bit configuration of the non-volatile memory, regardless of the display digit of the display section. Therefore, at the time of display, it is necessary to read the data numerical value in the non-volatile memory and convert it into the displayed numerical value. Therefore, the present invention proposes to divide the nonvolatile memory into memory units suitable for display.

[0007]

SUMMARY OF THE INVENTION An electronic odometer according to the present invention comprises a distance sensor for generating a pulse for each constant mileage of a vehicle, a non-volatile memory in which cumulative mileage data is written, and data in the non-volatile memory. And a calculation unit for calculating the latest vehicle mileage based on the count of the number of input pulses from the sensor and appropriately rewriting the data in the non-volatile memory, and a display for displaying the latest mileage. In the electronic odometer including and, the non-volatile memory is configured by a memory unit divided into digits of the displayed numerical value.

[0008]

[Operation] The vehicle travels a predetermined distance (unit travel distance),
When a predetermined number of pulse signals from the sensor are counted, the unit traveling distance is written in the memory unit, and at the same time, the latest traveling distance is displayed on the display. Moreover, in particular, since the memory section is divided corresponding to the digit of the displayed numerical value, the data in the memory section can be displayed without any special conversion.

[0009]

EXAMPLES Next, examples of the present invention will be described. The electronic odometer according to the present invention includes a sensor unit 1, an arithmetic processing unit 2, a memory unit 3 and a display unit 4, and the sensor unit 1
Is a distance sensor that generates a pulse for each constant traveling distance of the vehicle, the arithmetic processing unit 2 is formed by a CPU, counts pulse signals from the sensor unit 1, and outputs the pulse signal to the memory unit 3 for each predetermined traveling distance. Writing, reading, and output to the display unit 4 are performed.

The memory unit 3 is formed by a rewritable nonvolatile memory such as an EEPROM, and is a 10-digit.times.10-bit first digit memory unit 31, 1 word.times.1.
0-bit tenth digit memory unit 32, 100th digit memory unit 33, Thousands digit memory unit 34, Thousands digit memory unit 3
5 and 100,000th place digit memory section 36.

The display unit 4 is composed of a driver 41 and a display 42, and receives the output from the processing unit 4 to display the total traveling distance of the vehicle.

Thus, the vehicle has a predetermined distance (unit travel distance).
When a predetermined number of pulse signals from the sensor unit 1 are counted, the arithmetic processing unit 2 adds the unit traveling distance to the previous accumulated traveling distance to obtain the latest accumulated traveling distance, and the latest accumulated traveling is calculated. The distance is simultaneously written in the memory unit 3 and the latest mileage is displayed on the display 42. Writing to the memo part 3 corresponds to the digit of the displayed numerical value in the memory part 3, so that every time the vehicle travels a unit distance, one bit of the first digit memory part 31 changes from "0" to "1". When the number of rewrites from "0" to "1" reaches 10, the 1st bit of the tenth digit memory unit 32 is rewritten from "0" to "1", and all 10x10 bits are rewritten. When is finished, all bits are reset to "0" and rewriting is restarted. In addition, each upper-order digit memory unit rewrites one bit each time the immediately lower digit memory unit overflows and is reset.

Therefore, since the data in the memory unit 3 is recorded in each digit memory unit as a numerical value of a digit, the accumulated traveling distance can be displayed only by arranging and displaying the numerical values corresponding to the digits.

The memory unit 3 is only required to correspond to at least the digit of the displayed numerical value, and the memory unit of each upper digit is recorded as a 4-bit binary number instead of 1 word × 10 bits. , The BCD code may be interposed to obtain the display numerical value. Further, the memory unit of each digit may not be a single block, but a plurality of blocks may be left at the same time so that a plurality of records can be left at the same time to prevent the operation due to erroneous data.

[0015]

As described above, according to the present invention, in the electronic odometer having the non-volatile memory, the non-volatile memory is configured by the memory unit divided into each digit of the displayed numerical value, and the numerical value of each digit is independent. Since it is recorded as, the accumulated traveling distance can be known by simply reading the data numerical value of each digit, and there is an advantage that reading and display of the data is facilitated.

[Brief description of drawings]

FIG. 1 is a simple block diagram showing the configuration of an embodiment of the present invention.

[Explanation of symbols]

 1 sensor section 2 arithmetic processing section 3 memory section 4 display section

Claims (1)

[Claims] 1. A distance sensor that generates a pulse for each constant traveling distance of a vehicle, a nonvolatile memory in which integrated traveling distance data is written, a read of the data in the nonvolatile memory, and a count of the number of input pulses from the sensor. An electronic odometer including a calculation processing unit that calculates the latest vehicle mileage based on the data and appropriately rewrites data in a non-volatile memory, and an indicator that displays the latest mileage. Electronic odometer, characterized in that the memory is composed of a memory unit in which the display memory is divided for each digit of the displayed numerical value.